Energy Monitor

ABSTRACT

A system for detecting current magnitudes in a circuit breaker panel includes multiple 3-sensor magnometers placed over the main breaker and branch circuits in the circuit breaker enclosure. The sensors communicate with a local processing node, which analyzes the raw data to compensate for external and local interference, and provides an estimated current measurement. The estimated current measurement is then communicated back to a user system which can then use the information to better manage current input and output.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.16/035,373, filed on Jul. 13, 2018, which claims the benefit of priorityfrom U.S. Provisional Application No. 62/532,067, filed on Jul. 13,2017, both applications are entitled “Energy Monitor”, and are herebyincorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention pertains generally to devices and methods formeasuring electric current. More specifically, the present inventionpertains to vector magnetometer based detection of electric currents ina nearby wire. The present invention is particularly, but notexclusively, useful as a system for detecting current magnitudes in acircuit breaker panel.

BACKGROUND OF THE INVENTION

A variety of devices for detecting and measuring current have beeninvented since the development of the galvanometer. Modern ammeters areplaced in series with an electronic circuit in order to measure the flowof current through the circuit. Since an ammeter is placed in serieswith a circuit, it must present as little resistance as possible to thecircuit. Nonetheless, it is impossible to present absolutely zeroresistance to the circuit, so an ammeter causes a voltage drop in thecircuit. Additionally, in certain circumstances it may be inconvenientto have to add a new element to a circuit in order to measure current.

Certain methods which avoid inserting new circuit elements, such ascurrent clamps and Rogowski coils, are commonly used to measure ACcurrents. Since these rely on inductance to a sensing coil, they areeffectively transformers, drawing an amount of current proportional tothe current in the wire being measured. The jaws of a current clamp mustbe placed around the wire in which current is to be measured. Since aniron core is commonly used in a current clamp, the presence of a DCcurrent can permanently magnetize the core, distorting the accuracy ofthe clamp's future measurements. A Rogowski coil avoids the issue ofpermanent magnetization of the core. Nonetheless, the Rogowski coil mayrequire more careful positioning in order to obtain an accurate reading.Inductive methods for measuring current are also subject tointerference. Commercially available current clamps sometimes include alow-pass filter to partially mitigate the effects of interference oncurrent measurements. Nonetheless, for continuous, long-term monitoringof current flow, current non-invasive methods provide an expensivesolution.

Increasing concerns about energy use, its environmental effects, and thecost of energy—especially in regions that implement increased pricingfor peak-demand periods—have resulted in the development of systems formonitoring home and business energy use and controlling appliances tolimit energy consumption. Nonetheless, there remains a need for anefficient, easy, and inexpensive way to measure current flowing througha circuit breaker.

In light of the above, it would be useful to provide a device forplacement on a circuit breaker which would then measure the currentflowing through the circuit breaker without direct contact with thecurrent.

It would be further advantageous to provide an economical system formeasuring current magnitudes in a circuit breaker panel.

It would be further advantageous to provide an economical system formonitoring current magnitudes in a circuit breaker panel which providessimplified automatic calibration of errors in the positioning of thesensor relative to the breaker, and easy automatic calibration of othererror sources such as adjacent circuits.

It would be further advantageous to provide a system for measuringcurrents in a circuit breaker panel in which one or more measuringdevices could simply be placed over and adjacent to the breaker.

SUMMARY OF THE INVENTION

The present invention provides a system for measuring current magnitudesin a circuit breaker panel. Low cost, integrated vector (3-sensor)magnetometers typically used for electronic compasses provide sensorscapable of detecting the magnetic field associated with the conductivepath through a standard switchboard push-in circuit breaker and itsassociated output load wire. The magnetometers are selected for ameasurement rate of 120 Hz or greater to enable sufficient Nyquistbandwidth for detection of the 60 Hz waveform typical in the UnitedStates. They are also selected for sufficient resolution (no greaterthan about 1 amp RMS) to monitor the net current through a branchcircuit.

A preferred embodiment uses two or three sensors for a branch-typesingle phase circuit breaker, where one sensor is directly over thechosen breaker and the other one or two adjacent to it (either above,below, or both). For a main breaker, three sensors are incorporated intoa group where they are positioned with one directly over the incomingmain conductor for each phase, and the remainder to each side in asingle phase system, or between the two phases in a two-phase system.For a three-phase system, four or five sensors would be required, usingthe same type of positioning. The sensors are provided with an adhesiveor magnetic stick-on for easy attachment to the circuit breakers. Ingeneral, adhesive attachments are preferred to magnetic attachment, asthe latter could force the sensor into a lower gain mode and thus limitsensitivity.

The information collected by the sensors is sent to a processing elementthat will perform the necessary data acquisition and signal processingfunctions to reduce the magnetic field measurements to an estimate ofthe current carried by the conductor. The information thus collected andprocessed will be analyzed further to eliminate or reduce the effects ofexternal interference sources such as the geomagnetic field, and toeliminate or reduce the effects of local interference sources such ascurrents in adjacent circuit breakers.

The resulting data will be communicated back to a user system in theform of an estimated current measurement (either instantaneous, or withsome amount of noise rejection or moving average). The user system canthen use this information to better manage its amount of current inputand output.

BRIEF DESCRIPTION OF THE DRAWING

The nature, object, and advantages of the present invention will becomemore apparent to those skilled in the art after considering thefollowing detailed description in connection with the accompanyingdrawings, in which like reference numerals designate like partsthroughout, and wherein:

FIG. 1 is a diagram of the system for current magnitude detection of thepresent invention;

FIG. 2A is a diagram of a placement of sensors on a branch-typesingle-phase circuit breaker;

FIG. 2B is a diagram of a preferred placement of sensors on abranch-type single-phase circuit breaker or a single-phase main breaker;

FIG. 2C is a diagram of a preferred placement of sensors on a two-phasemain breaker;

FIG. 2D is a diagram of a preferred placement of sensors on athree-phase main breaker;

FIG. 3 is a representation of a device running an application to aid theuser in calibrating the system for current magnitude detection of thepresent invention;

FIG. 4 is a side view of a typical circuit breaker showing the currentpath through the breaker and the placement of a sensor of the presentinvention;

FIG. 5 is a perspective view of the sensor of the system for currentmagnitude detection of the present invention set up to detect currentpassing through a wire about five centimeters away from the sensor;

FIG. 6 is a front view of a sensor of the current invention placed on acircuit breaker;

FIG. 7 is a plot of measurements taken from the sensor depicted in FIG.4; and

FIG. 8 is a source-code listing demonstrating HMC8953 control andcommunication code for an Arduino Uno microcontroller.

DETAILED DESCRIPTION

The present invention is directed to a system for measuring currentcarried through a wire, and, in preferred embodiments, employed for thedetection of current magnitudes in a circuit breaker panel.

Referring initially to FIG. 1, an overview of the system for vectormagnetometer based detection of current magnitudes is shown. Integral tothe system is a current measurement device 110. The device 110 includesone or more sensors 112 which comprise 3-axis magnetometers, and isinstalled such that the sensors 112 are located near the paths ofcurrent 114 to be measured. In a common implementation, current paths114 are through the main breaker and branch circuits in a circuitbreaker enclosure, and the device 110 is installed such that the sensors112 are placed over the breakers. The number and positioning of thesensors is discussed more fully below.

In an embodiment, the sensors 112 are based on HMC5983 3-axis integratedcircuit magnetometers. Other sensors may be used, however, provided theyhave the sensing rate and resolution required. More generally, thesensors 112 are chosen from sensors able to switch back and forthbetween a high rate measurement of one-hundred twenty (120) Hz andabove, preferably one-hundred fifty (150) Hz and above, and a low rateof thirty (30) Hz or less, with minimum power standby to minimizeaverage power consumption. A one-hundred twenty (120) Hz or greatermeasurement rate enables sufficient Nyquist bandwidth for the detectionof the sixty (60) Hz AC waveform commonly found in U.S. residences.Lesser rates may be sufficient in certain foreign applications, andgreater rates may be necessary or desirable in certain situations.Nonetheless, in normal household and industrial applications, ameasurement rate of below four-hundred (400) to six hundred (600) Hz isused in preferred embodiments in order to minimize power consumption.Sensors meeting these requirements are generally available for less than$5 BOM.

The current flowing through current path 114 creates a magnetic field116 which is detected by the sensors 112. The information from thesensors 112 is sent to a local processing node 118. In preferredembodiments the local processing node 118 comprises a System on a Module(SOM) or System on a Chip (SoC), such as Nordic Semiconductor nRF51822BLE modules that incorporate a small ARM processor, a full BLE stack,and a wide variety of digital and analog I/O. The local processing node118 needs to be capable of on-board signal processing including inputscaling, simple math to remove known biases and compare signals betweendifferent sensor locations, bandpass filtering to extract the power linefrequency element of the signal, and vector math to further refine thesignals. With up to 10 sensors 112, each outputting six to eight bytesof data at between two hundred (200) and four-hundred (400) Hz, thetotal data rate of about twelve to about thirty-two kB/s would likelyresult in a processing requirement of less than ten to twenty MIPS forall of the required processing to maintain a real time operation. Intesting, I/O processing was performed on an Arduino Uno (about one tofour MIPS), and required about one thousand eight-hundred fifty (1850)microseconds, of which about one-thousand four-hundred fifty (1450) wasto communicate the output data at 115,200 bps to a laptop, so tensensors 112 worth of I/O processing on a minimum ten MIPS device islikely to only require about one-tenth of the overall cycle time.Overall data bandwidth from ten sensors 112 of about twenty to fortykbps is well within the capability of a single I2C or SPI busconnection.

Sensors 112 used in preferred embodiments of the present inventionprovide either I2C (two wire) or SPI (4 wire) communications to thelocal processing node 118. While the I2C is the simplest and requiresthe least traces to the sensors, sensors using fixed I2C addresses wouldrequire an I2C multiplexer or a number of local node I2C ports equal tothe number of sensors. While the multiplexer is not expensive ordifficult (less than $5 BOM), it does then mean that individual sensorswould each have a separate two-wire connection. If using SPI, then allthe attached sensors can share three of the four lines, with each havinga separate CS (chip select) line to be driven by the local node. Eitheroption works well with the present invention.

After detection by the sensors 112 and processing by the localprocessing node 118, the resulting data is provided in the form of anestimated current (either instantaneous, or with some amount of noiserejection or moving average). A communications element 120 sends theresulting data as an estimated current to a user system 122 such as theOrison™ Panel which can then use this information to better manage itsamount of current input and output. User system 122 may include anintelligent energy management system, a website having tools forreporting data from and managing the current measurement device 110, alocal computer with one or more programs which report data from andallow management of the current measurement device 110, a smartphoneapplication for reporting data from and managing the current measurementdevice 110, any related system known in the art, or any combination ofthe above. An end user device forming part of the user system 122 maycommunicate directly through the communications element 120, orindirectly via an intermediary such as a local or internet-connectedserver which handles communications with the current measurement device110 through the communications element 120. In preferred embodiments,communications are performed wirelessly, such as through Bluetooth,Bluetooth LE, or WiFi.

A power source 124 provides the necessary energy to the currentmeasurement device 110. Estimated power consumption for the sensors 112,using the HMC5983 magnetometers, is five to ten mW at maximummeasurement rate, and less than ten microwatts in standby. With anapproximate 2% duty cycle (2×60 Hz cycles of measurement every threeseconds), this equates to an average power consumption of two-tenths ofa milliwatt (i.e. 1500 hours for 10 sensors on a single 2500 mAh AAalkaline battery). A local processing node 118 and communicationsframework 120 using nRF51822 BLE modules is expected to consume lessthan thirty mW during full power transmit, and less than ten microwattsduring standby. Using the 20% duty cycle, this equates to an averagepower consumption of 0.6 mW for a total ten-sensor with local nodeconsumption of less than 2.6 mW, or about six months of operation onfour 2500 mAh AA alkaline batteries, or about twenty-three Wh per yearif a rechargeable battery is used. In a preferred embodiment, powersource 124 comprises an internal rechargeable battery with AA or AAAbattery backup, wherein the user is notified electronically to chargethe system when required.

Before operation, the device 110 needs to be installed and calibrated.The number and placement of the sensors may vary according to cable andbreaker box geometry, but in general two or three sensors are preferredfor a branch-type single phase circuit breaker, three sensors for asingle-phase or two-phase main breaker, and four to five sensors for athree-phase main breaker. The sensors are attached with a built-inattachment mechanism, which can either be adhesive or magnetic.Preferred placement on various types of circuit breakers is depicted inFIGS. 2A through 2D. Referring now to FIG. 2A, a representation of abranch-type single-phase circuit breaker is shown. Three sensors 112 areused, with a first directly over the breaker, a second above andadjacent to the first, and a third below and adjacent the first.Depending on the particular situation, it may be more practical to useonly two sensors 112. In such a case, the first would be placed directlyover the breaker, and the second adjacent to it and either above orbelow as desired.

Referring now to FIG. 2B, a representation of a branch-type single-phasecircuit breaker is shown. Three sensors 112 are used, with a firstdirectly over the breaker, and the second and third adjacent to it, onthe left and right, respectively. Three sensors 112 would also besufficient to measure two adjacent breakers. In such a case, one sensorwould be placed over each, and a third sensor would be placed off to oneside. An optional fourth sensor could be placed off to the other side.

The layout shown in FIG. 2B would also work for a single phase mainbreaker.

Referring now to FIG. 2C, a representation of a two-phase main breakeris shown. Three sensors 112 are used, with one sensor 112 over eachphase, and the third in between the two phases. An optional fourthsensor could be placed off to the side for greater accuracy. The use ofa fifth sensor on the opposite side of the fourth sensor is alsocontemplated.

Referring now to FIG. 2D, a representation of a three-phase main breakeris shown. Four or five sensors 112 are preferred for a three-phasesystem. In FIG. 2D, five sensors 112 are shown, with one sensor 112 overeach phase, and the remaining two sensors 112 in between the phases.Although five sensors are shown in FIG. 2D, accurate readings couldstill be obtained with only four sensors. In such a layout, either oneof the sensors in between the phases could be eliminated.

Once the sensors are installed, the system needs to be calibrated foruse. In particular, the system must determine what other magnetic fieldsare present, and what impact those have on the measurement of thedesignated breaker(s). In order to remove the local DC field duringinitial calibration, the sensor need only record field data over areasonable amount of time (several seconds), and remove via signalprocessing any 60 Hz variation of that field. This DC field vector canthen be removed from all future AC measurements.

Before monitoring of any specific variations of the designated branchbreaker, the system needs to determine the vector direction of nearby ACfields. This could be done as a preliminary method by having the useropen and close the nearby branch breakers on direction of a mobile appforming part of the user system 122—the system could then observe thesetransients (assuming there are existing loads on those circuits) todetermine the vector orientation of those nearby interfering fields. Ifthere is insufficient load, the user could be directed to add load tothose circuits (i.e. plug in a hair dryer or other appliance). For themain breaker, this type of calibration is likely unnecessary as itscalibration would be incorporated into other aspects of the calibration.

In general, any AC calibration method relies on the observation of knownvariable loading conditions. First, a baseline case is recorded, and themagnetic vector vs. time, which should, to first order, be asinusoidally varying magnitude vector of the value +/−the magnitude in afixed direction (but reversing magnitude in that direction at 60 Hz).

The user system 122 may be simply a computer or a display configured toprovide the acquired and processed data to an end user, such as adedicated display shipped with the system, a computer program, a websiteinterface, a mobile app, or a combination of several interface devices.However, preferred embodiments of the present invention are designed towork with intelligent energy monitoring and storage systems, such asthose sold as the Orison™ Panel. Such devices are capable ofcommunicating with the field measurement as well as creating positiveand negative net currents on the system with specific time-dependentvalues, allowing the system to calibrate itself very effectively byobserving the changes in AC fields given these known changes. Thesequences can be repeated in order to remove any other transient effectssuch as other variable loads.

During the initial calibration with an intelligent energy device such asthe Orison™ Panel, after performing the preliminary steps describedabove of measuring DC fields and AC vectors, the intelligent energydevice performs a sequence of step load changes and the resultsmonitored—for example, the system could provide a load of +5, +1, 0, −1,−5 Amps, each for 1 second, and repeat that 5 second sequence 10 times.This allows the sensors to confirm the field effects as follows:

For the branch circuit, the field vector of the different loads shouldbe in the same direction, so by comparing the magnitude/direction of themeasured result (which includes the nearby fields of other loads) tothat of the branch circuit with these known deltas, the relationshipbetween field and branch circuit load can be determined. Note that byhaving 2 or more sensors (one of which is directly over the designatedbreaker), load transients on other breakers can be removed (since, forexample, even though the field direction due to an adjacent vector isdifferent than the field direction of the chosen breaker, and thus twoadjacent breakers with different loads could have a vector sum that hasa direction identical to the designated breaker's field, having 1-2additional sensors adjacent to the designated breaker enables thesevectors to be removed). Additionally, since known load magnitudes areapplied, user variations (e.g. variations in which breakers are used andthe load wiring attached to them, or variations in how the sensor ispositioned, etc) can be calibrated out.

For the main breaker sensor, the load sequence enables detailedcalibration as well. With a 3-sensor group on a split-phase main, withthe sensors having a known position relative to each other, positionalvariations (since different panels have different feed conductorlocations, and the user installation may vary in where the sensor groupis place), the combined fields of the 2 feed conductors can be measuredand any other load transients removed.

An intelligent energy system may periodically repeat this calibrationsequence in order to gradually eliminate the effects of other loadingconditions (i.e. loads on circuit breakers N locations away), so thesystem will, over time, improve in accuracy.

Where an intelligent energy system is unavailable, the user may bedirected through the calibration process via written instructions, or,as mentioned above, an interactive process such as a mobile app. Theuser would activate or deactivate various existing loads on the circuit,allowing the device 110 to proceed through the calibration process.

In situations in which the user fails to calibrate the device 110, andno intelligent energy system is available to do so, software in thedevice 110 may be present which allows the device to attemptself-calibration over time. The self-calibration process comprisesmonitoring the various measurements over time and temporally correlatingthem to determine the unit vectors and relative fields to currentrelationships of the various sensors and circuits.

Once calibrated, the system can now monitor (at variable intervalsdepending on what is required) overall total load (main breaker current)and net current on the sensed branches—this can be used to determinepower arbitrage needs, inform the user about load variations, predicteffects of energy conservation methods, etc.

Where an intelligent energy system is used as the user system 122, itmay be configured to monitor the net current on its own branch, the netcurrent on a solar inverter supplied branch, and the net current on themain grid input. Since the sensor systems at the simplest approachdescribed above as a minimum viable product can only detect themagnitude of the current in a given branch (though, with careful signalprocessing it is likely possible to determine current direction bycomparing the field vector orientation vs. time compared to the mainbreaker sensors or other sensors measuring the opposite phase of a splitphase system, since inbound/outbound currents would have opposite phasesand field directions), it is possible to use the intelligent energysystem ability to vary its output/input to ensure net-zero output to thegrid. By varying the output by a small, known amount, the net current onthe main breaker can be compared to the Orison mean and dither values toconverge on a proper output for net-zero to the grid (i.e. if theintelligent energy system output is increased by 1 A, and the netcurrent on the main decreases by 1 A, leaving 2A, then the overalloutput value needs to be increased by ˜3A (but likely some value lessthan this will be chosen to avoid net output to grid), and so on atdecreasing variations until the system converges).

By comparing the net currents on the intelligent energy system branchwith a branch that has a solar inverter input, and potentially using thedither methods above if required, the intelligent energy system couldtailor its charge/discharge cycles to absorb a chosen amount of powerfrom a solar supply, which would enable energy arbitrage absorption(charging of the intelligent energy system) at any variable value fromzero to the instantaneous output of the solar system.

Some intelligent energy systems, such as the Orison™ system, may bedesigned with a mode of operation where they isolate their branchcircuit from the grid in a grid-loss situation (and thereby removingtheir ability to sense grid voltage upstream of that breaker). Thiscurrent sensing system can be used to determine when the grid returns bymonitoring the current in the main breaker (which, presumably, wouldhave some value due to loads that automatically come back on once poweris restored). Once that current is observed, the system could inform theintelligent energy system that the grid is now present, and alert theuser (or an automatic system) to close the islanding branch breaker andreconnect that circuit to the overall grid.

Referring now to FIG. 3, when the user system does not include anintelligent energy system that can handle the calibration process forthe user, a computing device such as a mobile phone 202 may be used toguide the user through the calibration process. In such circumstancesthe computing device, such as the mobile phone 202, forms part of theuser system 122 and communicates with the local processing node 118 viathe communications element 120. The communication may be performedthrough an intermediary server, as described above.

A program or app running on the computing device provides instructions204 to the user, which may include a visual representation 206 of theaction the user is expected to perform. The instructions 204 and thecorresponding visual representation 206, if any, will change from timeto time, cycling through the steps necessary for calibration. Forexample, at one point, the user may be requested to turn off a circuitbreaker next to a particular sensor. When the circuit breaker is turnedoff, the user acknowledges that the instruction has been performedthrough an acknowledgement button 208 or other manner appropriate to theuser interface of the computing device. Once the acknowledgement hasbeen made, the program notifies the local processing node 118, whichthen identifies the next measurements as representing zero current.Other steps may include turning on the circuit breaker, adding a loadsuch as a hair dryer or other appliance, and disconnecting a previouslyadded load. At each step, the user acknowledges the step has beenperformed, and the current measurement device takes measurements.

Alternatively, the local processing node 118 can be programmed toauto-detect when an instruction has been performed during a calibrationsequence, obviating the need for the user to make an actualacknowledgement. For example, the local processing node 118 can detectwhen the measurements taken by the sensors 112 drop and thus infer thatthe user turned off the circuit breaker as requested.

Referring now to FIG. 4, the AC current path 114 through a typicalcircuit breaker is depicted. Given typical circuit breaker dimensions, asurface-mounted sensor 112 on the visible, exposed surface of thebreaker, or immediately adjacent to it, would be on average about five(5) centimeters above both the internal current path 114 through thebreaker and from the load wire. The magnetic field 116 (not shown inFIG. 2) created by the current path 114 at the location of the sensor112 would be alternating between the outward and inward direction (thatis, coming directly out of or going directly into the page), with littleto no contribution in the up, down, left, and right directions.

Referring now to FIG. 5, a sensor 112 is depicted about five centimetersaway from a current path 114 consisting of a wire. In this setup, a DCpower supply 302 and a programmable load 304 were provided to test thesensor 112 of a preferred embodiment for suitability in measuringcurrent passing through path 114. The sensor 112 used comprises aHoneywell HMC5983 3-axis magnetometer using a two-wire I2C interface tooutput measurements at up to two-hundred twenty (220) Hz with aneffective noise of less than five (5) mGauss.

Using this setup, first a series of rapid measurements were takenwithout any current present in the test wire to determine both themagnitude and direction of the geomagnetic field, as well as any steadystate external fields. Based on the 0.73 mG/LSB gain of the HMC5983, thevector components of this field were +0.14, +0.21, −0.46 (x,y,z inGauss). This measurement was then subtracted in vector from any furthermeasurements to determine the field strength and direction change due tothe presence of current in the test wire. Then current of 1 A and 2 Awere passed through the wire, which should create a field in the +Zdirection of −0.04 and −0.08 Gauss, respectively for an infinitestraight wire. The values obtained in the initial testing were ˜0.06 and0.12 Gauss (with a direction unit vector Z value of >0.99). This is˜1.5× what was predicted and is due to the field contribution of theleft and right legs of the test wire and the return current path greenwire between the DC supply and the programmable load—as would bepredicted given their relative distance from the sensor. Future testingused different wire geometry to make this difference predictable.

Referring now to FIG. 6, the magnetometer sensor 112 of FIG. 3 wasmounted onto an existing, operating circuit panel for additionaltesting. For this application, the magnitude of the magnetic fieldassociated with the current on the branch breaker should oscillate atone-hundred twenty (120) Hz (since the magnitude is maximized twice persixty (60) Hz cycle but the magnetic field vector due to the currentwill rotate one-hundred eighty (180) degrees between each peak). Thesystem was then tested with a load of 1.7 A (rms) and 11 A (rms) byconnecting two different loads (a hot plate and a heat gun,respectively) to that circuit (which had no other active loadsattached), measuring their current draw using a conventional currentclamp meter, and comparing the resulting magnetic field waveformmagnitudes.

Referring now to FIG. 7, a plot of the measurements taken in conjunctionwith the testing described above is shown, in which units are in LSB vs.microseconds. The results depicted show the approach taken to beworkable, and artifacts that appear can be eliminated with calibrationand further signal processing. The waveform is a magnitude measurement,and thus is at one-hundred twenty (120) Hz in both cases. The overallenvelope modulation of about ten (10) Hz is likely due to theinteraction of the about two-hundred twenty (220) Hz sampling rate (i.e.110 Hz Nyquist bandwidth) and the about one-hundred twenty (120) Hzmagnitude modulation, resulting in a beat frequency of about ten (10) Hzwhen plotted in this fashion, as shown in the 11A X-component line inthe plot, the result is a sixty (60) Hz tone with little modulation.Second, the since this is only a single sensor, it is also detecting thefields due to current in the adjacent breakers and load wires—since thisis a two-hundred forty (240) V split-phase system the adjacent currentsare out of phase with the current through the breaker directly under thesensor. Thus, the field measured is the vector sum of the currents inthese adjacent breakers as well as the current in the main bus bars thatare perpendicular to the breaker and load wire axis. In preferredembodiments, multiple sensors are used as described above to enableelimination of these effects. Overall, the result is confirmatory asthere appears on simple inspection that the waveforms are proportionalto the current magnitudes, and the slope of peak-to-peak amplitude vs.current (˜30 mG/A) is quite close to the initial rough prediction of ˜40mG/A, a difference easily explained by a difference between the actualconductor-to-sensor distance and the 5 cm prediction, effects of theperpendicular main bus bars, and the non-infinite-straight-wire natureof the actual current path. Additionally, there is likely a source oferror that can be minimized due to how the ambient/baseline value wasremoved from the measurements. For simplicity, the baseline values wereaveraged over time to create an average field vector—ideally, the resultof a baseline measurement would be examined to determine a DC component(the geomagnetic vector) and the AC component (due to other currentcarrying AC conductors nearby, and filtered to determine the effectivefield unit vector and its magnitude based on a one-hundred eighty (180)degree reversal during the sixty (60) Hz current cycle) and these valuesused in the real signal processing method.

Referring now to FIG. 8, source code for communication and control ofthe HMC9853 is shown. In the experiment described above in conjunctionwith FIGS. 4 and 5, the communication, data acquisition, and signalprocessing node was based on an Arduino Uno, which performed thecontrol, configuration, and timing of the HMC9853 and also functioned asan I2C to USB translator to communicate the HMC9853 outputs to a laptopwhere the data storage and signal processing was performed using Excel.FIG. 6 provides the Arduino code as used in the experiments. For theexperiment, the Arduino board was reset, and the resulting data outputof the serial monitor was copied into excel, first for the baselinemeasurement, then for each experimental measurement. The baselinecomponent values were averaged, and then subtracted from each of theexperimental data points to yield the curves shown above. Conversionfrom binary magnitude to field units was done using the selected gainvalue of 0.73 mGauss/LSB.

While there have been shown what are presently considered to bepreferred embodiments of the present invention, it will be apparent tothose skilled in the art that various changes, combinations, andmodifications can be made herein without departing from the scope andspirit of the invention.

1. An intelligent management system for determining and managing netcurrent on a main grid input servicing a number of current paths, thesystem comprising: an energy monitor, the energy monitor for measuringcurrent magnitudes of a circuit at a circuit breaker panel so as togenerate and transmit raw current data, the circuit supplying one ormore current paths, the energy monitor including: a chipset having aplurality of integrated vector magnetometer sensor elements each fordetecting magnetic fields associated with current being carried by theone or more current paths through the circuit, the chipset further forgenerating raw current data for each respective current path of the oneor more current paths, each integrated vector magnetometer sensorelement having an individual address and being configured for measuringcurrent at a rate of 120 Hz or greater so as to enable sufficientNyquist bandwidth detection thereby generating sensed data forrespective current paths, an I2C multiplexer coupled to each of theintegrated vector magnetometer sensor elements for individuallyaddressing each sensor element, and being configured for transmittinginstructions to and receiving sensed data from the integrated vectormagnetometer sensor elements, an I2C bus coupled to the multiplexer andbeing configured for synchronizing transmission of the sensed data, aprocessor in communication with the integrated vector magnetometersensor elements via one or more of the I2C bus and the I2C multiplexer,the processor receiving the sensed data and formatting it fortransmission via the I2C bus, and a local processing node, coupled tothe energy monitor, and configured for receiving the sensed data, thelocal processing node including: a processor for processing the senseddata to generate estimated current data for each of the one or moreconductive paths, and a communications module, coupled to the processor,for transmitting the estimated current data of the current carried bythe respective conductive path; and an intelligent energy managementsystem server, coupled to the local processing node, the system serverbeing configured for receiving the estimated current data, and employingthe received estimated current data to determine the net currenttravelling through each of the current paths so as to facilitate themanaging of the net current on the main grid input.
 2. The intelligentmanagement system in accordance with claim 1, wherein each sensorelement is capable of cycling between a low and a high rate ofmeasurement.
 3. The intelligent management system in accordance withclaim 1, wherein each sensor element is configured for cycling between120 Hz and 600 Hz rate of measurement.
 4. The intelligent managementsystem in accordance with claim 1, wherein the local processing node isconfigured for performing on-board signal processing including: inputscaling, bias removal, band-pass filtering, and signal refinement. 5.The intelligent management system in accordance with claim 4, whereinthe system further comprises an intelligent energy storage unit incommunication with one or more of the local processing node and theintelligent energy management system server.
 6. The intelligentmanagement system in accordance with claim 5, wherein the system furthercomprises a client computing device in communication with one or more ofthe local processing node and the energy storage unit, the clientcomputing device for presenting a user interface to a user of the clientcomputing device, the user interface including controls for directingone or more of the local processing node, the intelligent energymanagement system server, and the intelligent energy storage unit. 7.The intelligent management system in accordance with claim 6, whereinthe client computing device comprises a smart phone, and the userinterface is presented to the user by the server via an applicationrunning on the smart phone.
 8. The intelligent management system inaccordance with claim 7, wherein the controlling of the amount of energybeing supplied to or removed from the selected current path is toeffectuate a net zeroing of the selected current path.
 9. An energymonitor, the energy monitor for measuring current magnitudes of acircuit at a circuit breaker panel so as to generate and transmit rawcurrent data, the circuit supplying a current path, the energy monitorincluding: a chipset having a plurality of integrated vectormagnetometer sensor elements each for detecting magnetic fieldsassociated with current being carried by one or more conductive pathsthrough the circuit breaker, the chipset further for generating rawcurrent information for each respective conductive path of the one ormore defined current paths, each integrated vector magnetometer sensorelement having an individual address and being configured for measuringcurrent at a rate of 120 Hz or greater so as to enable sufficientNyquist bandwidth detection thereby generating sensed data forrespective defined current paths; an I2C multiplexer coupled to each ofthe integrated vector magnetometer sensor elements for individuallyaddressing each sensor element, and being configured for transmittinginstructions to and receiving sensed data from the vector magnetometersensor elements; an I2C bus coupled to the multiplexer and beingconfigured for synchronizing transmission of the sensed data; aprocessor in communication with the integrated vector magnetometersensor elements via one or more of the I2C bus and the I2C multiplexer,the processor receiving the sensed data and generating raw currentinformation therefrom; and a communications module for transmitting theraw current information of the current so as to better manage its amountof current input and output.
 10. The energy monitor in accordance withclaim 9, wherein each sensor element is capable of cycling between a lowand a high rate of measurement.
 11. The energy monitor in accordancewith claim 10, wherein each sensor element is configured for cyclingbetween 120 Hz and a 600 Hz of measurement.
 12. The energy monitor inaccordance with claim 11, wherein the plurality of integrated vectormagnetometer sensor elements comprise a first set and a second set ofsensor elements, wherein at least one sensor element of each set isconfigured for being positioned on one side of the conductive path, andat least one sensor element of each set is configured for beingpositioned on an opposing side of the conductive path.
 13. The energymonitor in accordance with claim 12, wherein the plurality of integratedvector magnetometer sensor elements further comprises a third set ofsensor element, wherein at least one sensor element of the third set isconfigured for being positioned over the conductive path.
 14. The energymonitor in accordance with claim 13, wherein the I2C multiplexer isconfigured for sequencing the plurality of integrated vectormagnetometer sensor elements individually.